gecko-dev/accessible/base/NotificationController.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_a11y_NotificationController_h_
#define mozilla_a11y_NotificationController_h_
#include "EventQueue.h"
#include "nsCycleCollectionParticipant.h"
#include "nsRefreshDriver.h"
#ifdef A11Y_LOG
#include "Logging.h"
#endif
namespace mozilla {
namespace a11y {
class DocAccessible;
/**
* Notification interface.
*/
class Notification
{
public:
NS_INLINE_DECL_REFCOUNTING(Notification)
/**
* Process notification.
*/
virtual void Process() = 0;
protected:
Notification() { }
/**
* Protected destructor, to discourage deletion outside of Release():
*/
virtual ~Notification() { }
private:
Notification(const Notification&);
Notification& operator = (const Notification&);
};
/**
* Template class for generic notification.
*
* @note Instance is kept as a weak ref, the caller must guarantee it exists
* longer than the document accessible owning the notification controller
* that this notification is processed by.
*/
template<class Class, class Arg>
class TNotification : public Notification
{
public:
typedef void (Class::*Callback)(Arg*);
TNotification(Class* aInstance, Callback aCallback, Arg* aArg) :
mInstance(aInstance), mCallback(aCallback), mArg(aArg) { }
virtual ~TNotification() { mInstance = nullptr; }
virtual void Process()
{
(mInstance->*mCallback)(mArg);
mInstance = nullptr;
mCallback = nullptr;
mArg = nullptr;
}
private:
TNotification(const TNotification&);
TNotification& operator = (const TNotification&);
Class* mInstance;
Callback mCallback;
nsRefPtr<Arg> mArg;
};
/**
* Used to process notifications from core for the document accessible.
*/
class NotificationController : public EventQueue,
public nsARefreshObserver
{
public:
NotificationController(DocAccessible* aDocument, nsIPresShell* aPresShell);
NS_IMETHOD_(MozExternalRefCountType) AddRef(void);
NS_IMETHOD_(MozExternalRefCountType) Release(void);
NS_DECL_CYCLE_COLLECTION_NATIVE_CLASS(NotificationController)
/**
* Shutdown the notification controller.
*/
void Shutdown();
/**
* Put an accessible event into the queue to process it later.
*/
void QueueEvent(AccEvent* aEvent)
{
if (PushEvent(aEvent))
ScheduleProcessing();
}
/**
* Schedule binding the child document to the tree of this document.
*/
void ScheduleChildDocBinding(DocAccessible* aDocument);
/**
* Schedule the accessible tree update because of rendered text changes.
*/
inline void ScheduleTextUpdate(nsIContent* aTextNode)
{
if (mTextHash.PutEntry(aTextNode))
ScheduleProcessing();
}
/**
* Pend accessible tree update for content insertion.
*/
void ScheduleContentInsertion(Accessible* aContainer,
nsIContent* aStartChildNode,
nsIContent* aEndChildNode);
/**
* Process the generic notification synchronously if there are no pending
* layout changes and no notifications are pending or being processed right
* now. Otherwise, queue it up to process asynchronously.
*
* @note The caller must guarantee that the given instance still exists when
* the notification is processed.
*/
template<class Class, class Arg>
inline void HandleNotification(Class* aInstance,
typename TNotification<Class, Arg>::Callback aMethod,
Arg* aArg)
{
if (!IsUpdatePending()) {
#ifdef A11Y_LOG
if (mozilla::a11y::logging::IsEnabled(mozilla::a11y::logging::eNotifications))
mozilla::a11y::logging::Text("sync notification processing");
#endif
(aInstance->*aMethod)(aArg);
return;
}
nsRefPtr<Notification> notification =
new TNotification<Class, Arg>(aInstance, aMethod, aArg);
if (notification && mNotifications.AppendElement(notification))
ScheduleProcessing();
}
/**
* Schedule the generic notification to process asynchronously.
*
* @note The caller must guarantee that the given instance still exists when
* the notification is processed.
*/
template<class Class, class Arg>
inline void ScheduleNotification(Class* aInstance,
typename TNotification<Class, Arg>::Callback aMethod,
Arg* aArg)
{
nsRefPtr<Notification> notification =
new TNotification<Class, Arg>(aInstance, aMethod, aArg);
if (notification && mNotifications.AppendElement(notification))
ScheduleProcessing();
}
#ifdef DEBUG
bool IsUpdating() const
{ return mObservingState == eRefreshProcessingForUpdate; }
#endif
protected:
virtual ~NotificationController();
nsCycleCollectingAutoRefCnt mRefCnt;
NS_DECL_OWNINGTHREAD
/**
* Start to observe refresh to make notifications and events processing after
* layout.
*/
void ScheduleProcessing();
/**
* Return true if the accessible tree state update is pending.
*/
bool IsUpdatePending();
private:
NotificationController(const NotificationController&);
NotificationController& operator = (const NotificationController&);
// nsARefreshObserver
virtual void WillRefresh(mozilla::TimeStamp aTime);
private:
/**
* Indicates whether we're waiting on an event queue processing from our
* notification controller to flush events.
*/
enum eObservingState {
eNotObservingRefresh,
eRefreshObserving,
eRefreshProcessing,
eRefreshProcessingForUpdate
};
eObservingState mObservingState;
/**
* The presshell of the document accessible.
*/
nsIPresShell* mPresShell;
/**
* Child documents that needs to be bound to the tree.
*/
nsTArray<nsRefPtr<DocAccessible> > mHangingChildDocuments;
/**
* Storage for content inserted notification information.
*/
class ContentInsertion
{
public:
ContentInsertion(DocAccessible* aDocument, Accessible* aContainer);
NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(ContentInsertion)
NS_DECL_CYCLE_COLLECTION_NATIVE_CLASS(ContentInsertion)
bool InitChildList(nsIContent* aStartChildNode, nsIContent* aEndChildNode);
void Process();
protected:
virtual ~ContentInsertion() { mDocument = nullptr; }
private:
ContentInsertion();
ContentInsertion(const ContentInsertion&);
ContentInsertion& operator = (const ContentInsertion&);
// The document used to process content insertion, matched to document of
// the notification controller that this notification belongs to, therefore
// it's ok to keep it as weak ref.
DocAccessible* mDocument;
// The container accessible that content insertion occurs within.
nsRefPtr<Accessible> mContainer;
// Array of inserted contents.
nsTArray<nsCOMPtr<nsIContent> > mInsertedContent;
};
/**
* A pending accessible tree update notifications for content insertions.
* Don't make this an nsAutoTArray; we use SwapElements() on it.
*/
nsTArray<nsRefPtr<ContentInsertion> > mContentInsertions;
template<class T>
class nsCOMPtrHashKey : public PLDHashEntryHdr
{
public:
typedef T* KeyType;
typedef const T* KeyTypePointer;
nsCOMPtrHashKey(const T* aKey) : mKey(const_cast<T*>(aKey)) {}
nsCOMPtrHashKey(const nsPtrHashKey<T> &aToCopy) : mKey(aToCopy.mKey) {}
~nsCOMPtrHashKey() { }
KeyType GetKey() const { return mKey; }
bool KeyEquals(KeyTypePointer aKey) const { return aKey == mKey; }
static KeyTypePointer KeyToPointer(KeyType aKey) { return aKey; }
static PLDHashNumber HashKey(KeyTypePointer aKey)
{ return NS_PTR_TO_INT32(aKey) >> 2; }
enum { ALLOW_MEMMOVE = true };
protected:
nsCOMPtr<T> mKey;
};
/**
* A pending accessible tree update notifications for rendered text changes.
*/
nsTHashtable<nsCOMPtrHashKey<nsIContent> > mTextHash;
/**
* Update the accessible tree for pending rendered text change notifications.
*/
static PLDHashOperator TextEnumerator(nsCOMPtrHashKey<nsIContent>* aEntry,
void* aUserArg);
/**
* Other notifications like DOM events. Don't make this an nsAutoTArray; we
* use SwapElements() on it.
*/
nsTArray<nsRefPtr<Notification> > mNotifications;
};
} // namespace a11y
} // namespace mozilla
#endif // mozilla_a11y_NotificationController_h_